Introduction
The New York State Public Health Code provides that a person is dead when it is determined, in accordance with acceptable medical standards, that person has sustained either an irreversible cessation of all circulatory and respiratory functions or an irreversible cessation of the functioning of the entire brain, including the brain stem. This Policy provides the process and procedures to be used to determine whether a patient is dead due to brain death. The Policy is consistent with the New York State Department of Health and New York State Task Force on Life and the Law Guidelines dated November 2011.
Individual circumstances will vary from case to case, requiring physicians to rely upon their individual clinical judgment in determining whether all of these criteria are applicable to each individual case.In all cases, a high degree of caution and vigilance must be used to ensure that there is no possibility of a patient’s recovery.
Definition of Brain Death - A person who, in the recorded medical opinion, has fulfilled all prescribed criteria for establishing total, irreversible loss of function of the whole brain, including the brain stem, is clinically and legally dead. The three essential findings in brain death are coma, absence of brain stem reflexes, and apnea. Death occurs at the time when the prescribed criteria for brain death have been satisfied in accordance with standard test procedures.
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Responsibilities of Physicians Determining Brain Death
The diagnosis of brain death is primarily clinical. No other tests are required if, after an appropriate waiting period to determine reversibility, a single full comprehensive assessment of brain function, including testing of brain stem reflexes and a single apnea test, is conclusively performed. In the absence of either complete clinical findings consistent with brain death, or ancillary tests demonstrating brain death, brain death cannot be diagnosed and certified. Please see Appendix 1 for the determination of brain death in children less than 1 year old.
The steps for determining brain death are summarized below, and explained in more detail in the following pages:
Establish proximate cause and irreversibility of coma and monitor the patient for an appropriate waiting period in order to exclude the possibility of recovery.
Initiate the Hospital policy for notifying the health care agent or surrogate decision-maker; if the individual’s religious or moral objection to the brain death standard is known, or the health care agent or surrogate raises an objection to brain death based on religious or moral grounds, implement Hospital policies for reasonable accommodation.
Conduct and document a clinical assessment of brainstem reflexes.
Perform and document the apnea test.
Perform ancillary testing, if indicated.
Certify brain death.
Withdraw cardio-respiratory support in accordance with Hospital policies, including those for organ donation.
Only physicians who are privileged to make the determination of brain death may do so. The determination of brain death is limited to physicians in the specialties of Neurology and Neurosurgery. Postgraduate trainees in these areas may determine brain death if they have been privileged to do so.
Step 1: Establish Proximate Cause and Irreversibility of Coma
A prerequisite to the determination of brain death is the identification of the proximate cause and irreversibility of coma.
Possible causes: Severe head injury, hypertensive intracerebral hemorrhage, aneurysmal subarachnoid hemorrhage, hypoxic- ischemic brain insults, and fulminant hepatic failure.
The physician should assess the extent and potential reversibility of any damage, and also rule out confounding factors such as drug intoxication, neuromuscular blockade, hypothermia, or other metabolic abnormalities that cause coma but are potentially reversible. Establishing the cause and irreversibility of coma requires the physician to wait an appropriate period of time sufficiently long as is relevant for the individual patient (in practice, usually several hours) in order to rule out any confounding factors and the possibility of recovery.
The evaluation of a potentially irreversible coma should include, as may be appropriate to the particular case:
Clinical or neuro-imaging evidence of an acute CNS catastrophe that is compatible with the clinical diagnosis of brain death;
Exclusion of complicating medical conditions that may confound clinical assessment (e.g., no severe electrolyte, acid-base, or endocrine disturbance);
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Lack of significant hypothermia or hypotension:
Core temperature: ≥18y ≥ 36° C (96.8°F), 1-18y consider age specific norms, < 1y see Appendix 1
Systolic blood pressure: ≥18y ≥ 100 mm Hg (MAP ≥ 65mm Hg), 1-18y consider age specific norms, < 1y see Appendix 1
Exclusion of drug intoxication or poisoning. Patients admitted for treatment of drug overdose should have confirmatory tests to ensure that drug levels have decreased to clinically insignificant levels.
Where hypothermia was induced previously in a patient, additional vigilance is recommended. In such cases, a prolonged waiting period after the re-warming phase is completed may be appropriate.
If intoxicants such as barbiturates, benzodiazepines, or opioids are present, levels need not be zero, but should be in a range that would not normally be expected to interfere significantly with consciousness. If levels are unknown, a reasonable practice is to wait five half-lives (assuming normothermia and normal hepatic and renal function), or in the case of alcohol usage, the legal limit for driving (blood alcohol content 0.08%) may serve as a practical threshold below which an examination to determine brain death could reasonably proceed. A cerebral blood flow study that demonstrates absent intracranial blood flow is consistent with the diagnosis of brain death even in the presence of CNS depressants.
If neuromuscular junction blocking agents have been used, there should be evidence of neuromuscular transmission, i.e. deep tendon reflexes, other clinical muscle function, or responses to electrical stimulation of motor nerves, (presence of a train of 4 twitches with maximal ulnar nerve stimulation), before beginning the determination of brain death.
Step 2: Notify the Health Care Agent or Surrogate Decision-Maker
The physician [or physician designee] must make diligent efforts to notify the health care agent or, where no such health care agent exists, the surrogate decision-maker that the physician intends to proceed with the process for determining brain death. Consent need not be obtained. (See Policy No. [A3-113.9] for more information on designating a surrogate from a prioritized list of individuals under the Family Health Care Decisions Act).
Reasonable accommodation should be made for an individual’s religious or moral objection to the use of the brain death standard to determine death when such objection has been expressed by the patient prior to the loss of decision-making capacity, or the surrogate decision-maker. The physician should document the source of his or her knowledge about the patient’s beliefs in a progress note in the patient’s medical record.
Reasonable accommodations may include the continuation of artificial respiration under certain circumstances.
Objections to the brain death standard, other than religious or moral objections, such as family members' psychological inability to accept the death, do not require reasonable accommodation. In all circumstances, however, Hospital staff should demonstrate sensitivity and consider involving Hospital counselors to help family members accept the determination and fact of death.
Where family members object to invasive confirmatory tests, physicians should rely on the guidance of Hospital counsel and the Hospital’s Ethics Consultation Policy (See Policy No. [A3-119 ] for more information on the Ethics Committee).
Step 3: Clinical Assessment of Brain Stem Reflexes
The brain death determination requires one clinical assessment of brain function followed by an apnea test after a period of waiting necessary to exclude the possibility of recovery. However, if the possibility of recovery has not been excluded, these examinations should be deferred.
The following clinical indications verify the occurrence of brain death:
Coma - No evidence of responsiveness. Eye opening or eye movement to noxious stimuli is absent. Noxious stimuli should not produce a motor response other than spinally mediated reflexes.
Absence of brainstem reflexes:
Absence of pupillary response to bright light in both eyes. Usually the pupils are fixed in midsize or dilated position (4-9 mm)
Absence of ocular movements using oculocephalic testing (only when no fracture or instability of the cervical spine or skull base is apparent or may be suspected clinically) and oculovestibular reflex testing
Absence of corneal reflexes
Absence of facial muscle movement in response to a noxious stimulus
Absence of pharyngeal (gag) or tracheal (cough) reflexes
Confounding factors: The following conditions may interfere with the clinical diagnosis of brain death. In such instances, ancillary tests may be necessary.
Severe facial or cervical spine trauma, or facial deformity confounding cranial nerve assessment
Toxic levels of CNS-depressant drugs or neuromuscular blocking agents
Severe electrolyte, acid-base, or endocrine disturbance (defined by severe acidosis or laboratory valuesmarkedly deviated from the norm)
Severe chronic pulmonary disease or severe obesity resulting in chronic retention of CO2
Clinical observations compatible with the diagnosis of brain death: The following manifestations are occasionally seen and should not be misinterpreted as evidence for brainstem function.
Spontaneous movements of limbs (when due to spinal activity)
Respiratory-like movements (shoulder elevation and adduction, back arching, intercostal expansion without significant tidal volumes)
Sweating, flushing, tachycardia
Normal blood pressure without pharmacologic support or sudden increases in blood pressure
Absence of diabetes insipidus
Deep tendon reflexes; superficial abdominal reflexes; triple flexion response
Babinski reflex
The Apnea Test: Generally, the apnea test is the final step in the determination of brain death, and is performed after establishing the irreversibility and unresponsiveness of coma, and the absence of brainstem reflexes. Before performing the apnea test, the physician must determine that the patient meets the following conditions:
Core temperature > 36°C or 96.8°F
PaCO2 35-45 mm Hg.
Normal PaO2. (Option: pre-oxygenation for at least 10 minutes with 100% oxygen to PaO2 > 200 mm Hg)
Normotension. Adjust fluids and (if necessary) vasopressors to a systolic blood pressure ≥ 100 mm Hg (option: MAP ≥ 65 mm Hg)
After determining that the patient meets the prerequisites above, the physician should conduct the apnea test as follows:
Connect a pulse oximeter
Disconnect the ventilator. Apnea can be assessed reliably only by disconnecting the ventilator, as the ventilator can sense small changes in tubing pressure and provide a breath that could suggest breathing effort by the patient where none exists.
Deliver 100% O2, 6 L/min. by placing a catheter through the endotracheal tube and close to the level of the carina. (Option: use a T-piece with 10cm H2O CPAP and deliver 100% O2, 12L/min).
Draw a baseline arterial blood gas.
Look closely for respiratory movements (abdominal or chest excursions that produce adequate tidal volumes) for 8-10 minutes.
Measure arterial PaO2, PaCO2, and pH after approximately 8-10 minutes and reconnect the ventilator.
Connect the ventilator if, during testing, the systolic blood pressure becomes < 90 mm Hg (or below age appropriate thresholds in children <18 years of age) or the pulse oximeter indicates significant oxygen desaturation (<85% for > 30 seconds), or cardiac arrhythmias develop; immediately draw an arterial blood sample and analyze arterial blood gas.
Potential results:
If respiratory movements are absent and arterial PaCO2 is ≥ 60 mm Hg (Option: 20 mm Hg increase in PaCO2 over a baseline normal PaCO2), the apnea test result is positive (i.e. it supports the diagnosis of brain death).
If respiratory movements are observed, the apnea test result is negative (i.e. it does not support the clinical diagnosis of brain death).
If PaCO2 is < 60 mm Hg and PaCO2 increase is < 20 mm Hg over baseline normal PaCO2, the result is indeterminate.
If adequate blood pressure and oxygenation can be maintained, the apnea test can be repeated for a longer period of time (10-15 minutes) or an ancillary test can be considered if the result is indeterminate.
Step 5: Performing Ancillary Testing
When the full clinical examination, including both assessments of brain stem reflexes and the apnea test, is conclusively performed, no additional testing is required to determine brain death. In some patients, facial or cervical injuries, cardiovascular instability, or other factors may make it impossible to complete parts of the assessment safely. In such circumstances, an ancillary test verifying brain death is necessary. These tests may also be used to reassure family members and medical staff. Based on clinical indications, ancillary testing may sometimes precede other aspects of the determination of brain death.
Documentation should indicate which parts of the clinical examination could not be completed safely, along with the reason. Even when ancillary testing is consistent with brain death, as when absent cerebral blood flow is documented, brain death protocols still require assessment of coma, brainstem reflexes and an apnea test, except in circumstances where such tests cannot be performed.
Any of the following suggested tests may produce similar results in patients with catastrophic brain damage who do not (yet) fulfill the clinical criteria of brain death. The diagnosis of brain death rests on the clear determination of the cause of coma, the elimination of potentially confounding factors, and the results of the clinical exams and those of ancillary tests as indicated.
The choice of an ancillary test is dictated in large part by practical considerations, i.e. availability, advantages and disadvantages. Available ancillary tests are listed below, in alphabetical order, along with the findings consistent with brain death and complicating factors:
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Angiography (conventional, computerized tomographic, and magnetic resonance): Brain death confirmed by demonstrating the absence of intracerebral filling at the level of the carotid bifurcation or Circle of Willis. On CT angiography, opacification may be seen in proximal portions of the anterior and middle cerebral arteries. The external carotid circulation typically is patent, and filling of the superior sagittal sinus may be delayed.
MRI angiography can be challenging in an ICU patient because of magnet incompatibility with lines, ventilator tubing and other hardware.
CT angiography commonly demonstrates blood flow in patients who are brain dead.
Cerebral arteriography: This test is often difficult to perform in a critically ill, unstable patient.
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Electroencephalography (EEG): Brain death confirmed by documenting the absence of electrical activity during at least 30 minutes of recording that adheres to the minimal technical criteria for EEG recording in suspected brain death as adopted by the American Electroencephalographic Society, including 16-channel EEG instruments.
- The ICU setting may result in false readings due to electronic background noise creating artifacts.
Cerebral Scintigraphy (HMPAO) (Nuclear Brain Scanning): Brain death is confirmed by absence of uptake of isotope in brain parenchyma and/or vasculature, depending on isotope and technique used (“hollow skull phenomenon”).
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Transcranial Doppler Ultrasonography: Brain death confirmed by small systolic peaks in early systole without diastolic flow, or reverberating flow, indicating very high vascular resistance associated with greatly increased intracranial pressure.
- Since as many as 10% of patients may not have temporal insonation windows because of skull thickness, the initial absence of Doppler signals cannot be interpreted as consistent with brain death.
Step 6: Certification of Brain Death
Brain death can be certified by a single physician privileged to make brain death determinations. However, before a patient can become an organ donor, New York State law requires that the time of brain death must be certified by the physician who attends the donor at his death and one other physician, neither of whom shall participate in the procedures for removing or transplanting organ(s). This requirement ensures that the clinical assessment and any ancillary testing meet the accepted medical standards, and that all participants can have confidence that the brain death determination has not been influenced by extraneous factors, including the needs of the potential organ recipients.
When two physicians are required to certify the time of death, i.e., when organ donation is planned, the second physician must review and affirm that the medical record and data fully support the determination of brain death. Any aspect of the clinical assessment, apnea test, or ancillary test (if applicable) may be performed again if the second physician believes it is indicated to make his or her determination concerning brain death. The second physician must have attending privileges as a member of the medical staff of the Hospital, but need not be privileged to perform brain death determinations. However, he or she should have a thorough understanding of the tests involved.
Medical Record Documentation: All phases of the determination of brain death should be documented in the medical record. A checklist is appended at the end of this policy which may be used to document that all steps were followed. The medical record must indicate:
Etiology and irreversibility of coma
Absence of cerebral unresponsiveness
Absence of brainstem reflexes during an exam
Absence of respiration with PaCO2 ≥ 60 mm Hg, (or ≥20 mm Hg over baseline normal PaCO2)
Justification for, and result of ancillary tests, if used
Step 7: Withdraw cardio-respiratory support in accordance with Hospital policies, including those for organ donation
Individuals who have been declared dead, and for whom permission has been given for organ donation, will be continued on existing support systems, including such measures as CPR, preferably in an intensive care setting. This will be done for the sole purpose of maintaining perfusion of the organs until they are removed. See Policy on organ donation for more information.
Deceased individuals not to be involved in organ transplantation will have support systems discontinued by a staff physician.
Step 8: Disconnect Ventilator
If a patient has been determined to be brain dead and the ventilator is to be disconnected, family members should be given the opportunity to be present when the ventilator is disconnected, if they so wish. However, they should be advised of the possible occurrence of isolated spinal movements as described below. When organ donation is contemplated, ventilatory support will conclude in the operating room and family attendance is not appropriate.
Isolated spinal movements compatible with brain death include deep tendon reflexes including stereotypic triple flexor responses in the lower extremities. These include spontaneous slow movements of an arm or leg. Bizarre movements of entirely spinal origin may sometimes occur in brain dead patients. Also, coordinated movements can occur with shoulder elevation and adduction, back arching and the appearance of intercostal muscle contraction without detectable tidal volumes.
Appendix 1: Determination of Brain Death in Children Less Than One Year of Age
General Policy Statement. The brains of infants and young children have increased resistance to damage and may recover substantial functions even after exhibiting unresponsiveness on neurological examination for longer periods as compared to adults. When applying neurological criteria to determine death in children younger than one year, longer waiting periods are required.
The patient must not be significantly hypothermic or hypotensive for age.
Waiting Periods: The recommended waiting period depends on the age of the patient and the laboratory tests utilized. Ages listed assume the child was born at full term. Between the ages of 7 days and 2 months, the minimum interval should be 48 hours. Between the ages of 2 months and 1 year, an interval of at least 24 hours should be used.
Reliable criteria have not been established for the determination of brain death in children less than 7 days old.
Seven days to two months: Two examinations and electroencephalograms (EEGs) should be separated by at least 48 hours.
Two months to one year: Two examinations and EEGs should be separated by at least 24 hours. A repeat examination and EEG are not necessary if a concomitant radionuclide or other angiographic study demonstrates no visualization of cerebral arteries.
<###Appendix 2: Brain Death Checklist>